The service, Google's fourth foray into social networking, experienced strong growth in its initial years, although usage statistics have varied, depending on how the service is defined. User engagement has been relatively low.[4] Three Google executives have overseen the product, which is undergoing substantial changes. These include the re-launch of two core Google+ functions, communications and photos, as standalone products, as well as refocusing the service on shared interests. Males of ages between 24–36 have comprised the largest share of the user base.

Google+ is the company's fourth foray into social networking, following Google Buzz (launched 2010, retired in 2011), Google Friend Connect (launched 2008, retired by March 1, 2012) and Orkut (launched in 2004, as of 2013[update] operated entirely by subsidiary Google Brazil – retired in September 2014[5]).

Google+ launched in June 2011. Features included the ability to post photos and status updates to the stream or interest based communities, group different types of relationships (rather than simply "friends") into Circles, a multi-person instant messaging, text and video chat called Hangouts, events, location tagging, and the ability to edit and upload photos to private cloud-based albums.[6][7]

Between 2011 and 2012, the number of active users on Google+ grew significantly, but the average time those users spent on the site was a small fraction of that on comparable social media services. Assessments of Google+ growth have varied widely because Google first defined the service as a social network,[6] then later as "a social layer across all of Google's services", allowing them to share a user's identity and interests.[15] According to Ars Technica, Google+ signups are "often just an incidental byproduct of signing up for other Google services."[16][17][18]

In private beta, Google+ reached 10 million users just two weeks after the launch.[19] In a month, it reached 25 million.[20] In October 2011, the service reached 40 million users, according to Larry Page.[21] Based on ComScore, the biggest market was the United States followed by India.[22] After nearly three months of operation, it hit 50 million users, whereas other social networking sites such as MySpace took 1,046 days to reach that level; Twitter 1,096 days; Facebook 1,325 days; and LinkedIn 2,354 days .[23] By the end of the year Google+ had 90 million users.[24] According to Experian Hitwise, an Internet metrics firm, the number of U.S. visits to Google+ surpassed 49 million during the one-month period ending December 11, 2011, a 55% increase from the one-month period ending November 11, 2011.[25] According to independent analysis of its growth in December 2011, the site was adding an estimated number of 625,000 new users a day.[26][27] In just under a day in July 2011, the Google+ iPhone app became the most popular free application in the Apple App Store.[28]

In October 2013, approximately 540 million monthly active users made use of the social layer by interacting with Google+'s enhanced properties, like Gmail, +1 button, and YouTube comments.[10] Some 300 million monthly active users participated in the social network, interacting with the Google+ social networking stream.[1][29][30]

But user engagement on Google+ was low compared with its competitors. ComScore estimated that users averaged just 3.3 minutes on the site in January 2012, versus 7.5 hours for Facebook.[14][31] In March 2013, average time spent on the site remained low: roughly 7 minutes, according to Nielsen, not including traffic via apps.[4] In February 2014, The New York Times likened Google+ to a ghost town, citing Google stats of 540 million "monthly active users", but noting that almost half don't visit the site. The company replied that the significance of Google+ was less as a Facebook competitor than as a means of gathering and connecting user information from Google's various services.[32]

In April 2014, Vic Gundotra, the executive in charge of Google+, departed the company[33] with management responsibility going to David Besbris. By March 2015, Google executive Bradley Horowitz, who had co-founded Google Plus with Gundotra, had replaced Besbris, becoming vice president of streams, photos, and sharing. In an interview with Steven Levy published on May 28, 2015, Horowitz said that Google+ was about to undergo a "huge shift" that will better reflect how the service is actually used. By this time, two core Google+ functions, communications and photos, had become standalone products.[34][35][36][37]Google Photos, Google's photo and video library, was announced at the May 2015 Google I/O conference.[38]Google Hangouts, Google's communications platform, was announced two years earlier, also at Google I/O.[39]

In July 2014, Horowitz posted that Google+ would focus on shared interests; features not supporting "an interest-based social experience" are being removed. The company is also eliminating the Google+ social layer; users will no longer require a Google+ profile to share content and communicate with contacts. The transition began with YouTube, where a Google+ profile will not be required to create, upload, or comment on a channel. YouTube comments will no longer appear on Google+ or vice versa.[40][41][42][43]

Google+ user base was roughly 60% male and 25% female as of November 2013, and 15% "other" or unknown.[44] Early adopters of Google+ in mid-2011 were mostly male (71.24%), and the dominant age bracket (35%) was between 25 and 34.[45] An August 2011 survey estimated that 13% of U.S. adults had joined Google+.[46]

A Google+ User profile is a public visible account of a user that is attached to many Google properties. It includes basic social networking elements like a profile photo, about section, background photo, previous work and school history, interests, places lived and an area to post status updates.[47] It also includes several identity service sections, such as a contributor and other profiles area that let one link their "properties across the web". These section optionally link to other social media accounts one has, any blogs one owns or have written or sites one is a contributor to. This area is used for Google Authorship.[48][49] Customized or Vanity URLs were made available to the public starting on October 29, 2013 to any account that is 30+ days old and has a profile photo and at least 10 followers.[50] Google removed author photos from search results in June 2014[51] and in August 2014 Google has stopped showing authorship in search results, both photo and author name.[52][53]

Circles is a core feature of the Google+ Social Platform. It enable users to organize people into groups or lists for sharing[54] across various Google products and services. Organization of circles is done through a drag-and-drop interface. Once a circle is created, a Google+ user can share specific private content to only that circle. For example, work themed content can be shared with only colleagues, and one's friends and family could see more personal content and photos. The option to share Public or with Everyone is always available.[55] Since September 26, 2011 users can share Circles; it's a one-time share, so if the creator of the Circle updates the members, people's shared copies won't be updated.

Another function of Circles is to control the content of one's Stream. A user may click on a Circle on the left side of the page and the Stream portion of the page (the center) will contain only posts shared by users in that Circle. For the unsegmented Stream (includes content from all of a user's Circles), each Circle has a "slider" configuration item with four positions: nothing, some things, most things, and everything. The nothing position requires the user to select (click on) the Circle name explicitly to see content from users in that Circle. The everything setting as its name implies filters nothing out from people in that Circle. The remaining two positions control the quantity of posts which appear in one's main Stream, but the algorithm controlling what shows has not been disclosed.

In the "Stream", which occupies the middle of three columns on the page, users see updates from those in their Circles. There is an input box which allows users to enter a post. Along with the text entry field there are icons to upload and share photos and videos. The Stream can be filtered to show only posts from specific Circles.

Starting in November 2011, Google+ profiles are used as the background account for many Google Services including YouTube, Gmail, Google Maps, Android, Google Play, Google Music, Google Voice, Google Wallet, Google Local and more.[16][17] As of January 10, Google Search is customized with a feature called Search Plus Your World, which inserts content shared on Google+ profiles and brand pages under Web Search results, if one is logged into their Google+ account while using it.[56] The feature, which is opt-in, was received with controversy over the emphasis of Google+ profiles over other social networking services. The feature builds upon the earlier "Social Search" feature which indexes content shared or published by authors; "Social Search", however, relied partly upon returns from non-Google services, such as Twitter and Flickr. Google and Twitter had a contract that expired in July 2011 which is the reason Tweets are no longer shown.[57]

U.S. President Barack Obama interacts with YouTube and Google+ Hangout users in his first completely virtual interview, aired live on January 30, 2012.[58]

Hangouts are free video conferencing calls with up to 10 people, done through the Google+ website or mobile app. Many apps can be used inside the hangout, allowing users to share documents, a scratchpad, or their screens with other users, as well as many built-in apps such as YouTube, Google Docs, and the new Capture. Third-party apps built using the Hangout API are also available[59]

Mobile Hangouts has supported Android 2.3+ devices with front-facing cameras since September 20, 2011. As of July 10, 2012 Google+ users on iOS are able to use Hangouts on iPhone and iPad.

Hangouts On-Air gives users the ability to create instant webcasts over Google+ and live-streamed to their connected YouTube channel. The broadcasts can also be recorded for later retrieval. This feature, announced on September 20, 2011, was initially limited to some videocast personalities, but the tool has since been made publicly available to all Google+ users. The first publicly broadcast Hangout was with The Black Eyed Peas’ will.i.am on the night of September 21, 2011.[60] The feature became available at a large scale on May 7, 2012.[61] The feature is not available to users under age 18 or from China, Thailand, or Vietnam.[62]

Hangouts on Air create YouTube video files that can be shared like all other YouTube videos socially, so beginning December 2013, future G+ HOA events scheduled on Google+ will immediately and automatically create YouTube video files, that are indexed for Google search engine results (SERPs) instantly. Then audiences can engage with the video page (YouTube comments) and event page (Google+ event with video embedded), leading up to the live video recording event, which gives you until the live recording to generate live audience and panel participants. With an extended planning period (3 or more months), Google+ Hangouts on Air live recording events can 1) include relevant business celebrities & influencers as guests on the video chat panel, and 2) pre-promote, livestream, and distribute the YouTube video code embedded into the digital channels of established-audience mass media brands, like Forbes.com. Inviting thought leaders and brand advocates to participate in a pre-planned and pre-promoted live interactive roundtable, town hall, webinar, chat show or other format, allows the host business to effectively "sponsor" the media production and generate brand awareness, similar to publicity, for being known as the person/organization who "always hosts that show".[63]

Google+ Pages was launched on November 7, 2011 to all users, which allows businesses to connect with fans.[65][66][67] It allows entities which are not individuals (such as organizations, companies, and publications) to set up profiles, or "pages", for the posting and syndication of posts. It is similar to Facebook Pages.

Google+ Badges was quietly rolled out to select enterprises beginning November 9, 2011 and officially released to the public on November 16.[68] Badges are sidebar widgets which embed "Add to Circles" buttons and drop-down lists into off-site websites and blogs, similar to Facebook's Like Box widgets. This was officially treated by Google as a replacement for the older Google Friend Connect and its widgets, and GFC was announced by Senior Vice President of Operations Urs Hölzle on November 23, 2011, as scheduled to be retired by March 12, 2012 on all non-Blogger sites in favor of Google+ Page Badges.[69]

Google+ Views was introduced on April 1, 2014. It features a "view counter", which is displayed on every user’s profile page. The view counter shows the number of times the user's content has been seen by others, including photos, posts, and profile page.[70]

Google+ Communities: Released December 6, 2012, Google+ Communities allow users to create ongoing conversations about particular topics.[71] Google+ Communities can also be created and managed under Google+ Page accounts.

Currently (April 2014) between Communities and Hangouts on the main mobile menu, Locations is mostly the service that was Latitude. It allows the account holder to share their location with a person, circle or circles. The location can be as accurate as the GPS on the mobile device or can be set to only show city. That distinction on the map is shown by the shape of the avatar or profile photo. Further, if the device is between locations or, in the US, on a state line, the location will be given as the state or as "United States". If the location isn't updated by a mobile device or Web browser, the profile shows the static location named in the profile after 24 hours. (Its life earlier in 2014 was a week.)

Google+ Events: Released at Google I/O on June 27, 2012, Google+ Events allows users to add events, invite people, and then share photos and media in real-time from the event. The program is integrated with Google Calendar, and is posed as a direct competitor to similar features offered by Facebook.[72]

On June 11, 2014, Google combined Google Places and Google+ Local Business Pages with the Google My Business product. The product uses the interface of Google+ but has many more features including insights and analytics.[74] On May 30, 2012, Google Places was replaced by Google+ Local, which now integrates directly with the Google+ service to allow users to post photos and reviews of locations directly to its page on the service. Additionally, Google+ Local and Maps also now feature detailed reviews and ratings from Zagat, who was acquired by Google in September 2011.[75]

Google+ Creative Kit is an online photo editor integrated to Google+ on October 27, 2011,[73] which is essentially Picnik, integrated earlier to Picasa Web Albums.

Auto Awesome: Released at Google I/O in 2013, the feature applies special effects, manually (with Android) or automatically, often using multiple sequential shots. Effects include composite motion in a single image, short animation, photobooth style, and high-dynamic range rendering (HDR).[76]

"Instant Upload" is specific to mobile devices; it stores photos or videos in a private album for sharing later.[54]

A "Data Liberation" option provides the ability to download one's content from Google+.[79]

"Search in Google+" allows users to search for content within Google+. Users type what they're looking for into the Google+ search box, and Google will return relevant people and posts, as well as popular content from around the web.[80]

Hashtags, where "#" is written before a word or CamelCase, are hyperlinked to the most recent or highest-trending search results within Google+ containing the term. This, a feature which gained notoriety as a microblogging practice on Twitter, was implemented as a Google+ feature on October 12, 2011. Autocompletion came on January 17, 2012.[81]

"New Features for Google+ Mobile" Since the launch of Google+, Google has been adding and making changes to many features. On September 30, 2011, the company released a list of changes and additions to Google+ mobile which include:[82]

Broadened SMS support so that users in the 185 countries including U.S. and India can now post to Google+, receive notifications, and respond to group messages via SMS.[83] They have also made it easier to +mention someone from a mobile device. Now, to +mention another user, one simply writes +[their name] inside a post or comment. In order to +1 comments more easily, users are now able to +1 them directly from their iOS devices. They also introduced this feature to the Android app in December 2011.

Select public figures have verified names. Google determines whether a particular profile warrants verification. The purpose is to indicate to site visitors whether a particular profile belongs to who one would generally expect the name to be, and not someone who coincidentally has the same name as a public figure. Verified identity profiles have a checkmark logo after their name. Examples of profiles bearing the verified name badge include Linus Torvalds, William Shatner, Leo Laporte, Mark Zuckerberg, Larry Page, and Sergey Brin.[84]

"Messenger" (formerly: Huddle) is a feature available to Android, iPhone, and SMS devices for communicating through instant messaging within Circles. Additionally, users can share photos in Messenger between their Circles.[54] This feature was removed in August 2013 since it is superseded by Hangouts.[86]

"Sparks" is a front-end to Google Search, enabling users to identify topics they might be interested in sharing with others. "Featured interests" sparks are also available, based on topics others globally are finding interesting.[54] Sparks is accessed as a pull-down from search results and helps to keep users informed of the latest updates on the topics of their interest. Sparks was removed sometime in November 2012.[87]

"Games" (social gaming) had 16 games when launched on August 11, 2011,[88] which expanded to 44 a few months later, but by April 2013 there were 38 since some games were removed by the owner.[89] Unlike Facebook games, Google+ games are located under a games tab, which gives games less visibility,[90] and had separate notifications from the rest of a user's notifications.[90] All games were deleted from Google+ in June 2013.[91]

Ripples, introduced on October 27, 2011, was a visualization tool, showing how resharing activity happens regarding a public post. One could replay the public share's activity, zoom in on certain events, identify top contributors, view statistics about average chain length, the most influential people in the chain, the language of the sharers, etc.[73] The feature was removed in May 2015.[93]

According to Joseph Smarr, one of the Google+ team's technical leads, Google+ is a typical Google web application: it uses Java servlets for the server code and JavaScript for the browser-side of the UI, largely built with Google's Closure framework, including the JavaScript compiler and the template system. They use the HTML5 History API to maintain good-looking URLs in modern browsers despite the AJAX app. To achieve fast response times Google often renders the Closure templates on the server side before any JavaScript is loaded; then the JavaScript finds the right DOM nodes, hooks up event handlers, etc. The back ends are built mostly on top of BigTable and Colossus/GFS, and other common Google technologies such as MapReduce.[2]

When joining the service, new users are asked for real-name and gender disclosure, which at launch was shared as public information.[94] The gender selector has options for "Male", "Female", and "Other". The mandatory public gender exposure led to criticism for making older Google profiles public.[95] In response, Google made changes to the service that allows users to control the privacy settings of their gender information.[96] Google's justification for requiring gender information is that it uses that information to inform its usage of the terms "he", "she", and "they" in their delivery of information to users of the service. If a user decides to make the gender portion of the profile private, the language used to convey information becomes gender-neutral, using the singular they in place of gender-specific pronouns.[97]

In July 2011, Google+ required users to identify themselves using their real names and some accounts were suspended when this requirement was not met.[105][106] Google VP Bradley Horowitz stated that a violation of the terms of service will only affect the service whose terms were violated[clarify] and not any of the other services that Google provides.[107] However, there were early reports of account holders being temporarily locked out of all of Google services.[108]

On October 19, 2011, at the Web 2.0 Summit, Google executive Vic Gundotra revealed that Google+ would begin supporting pseudonyms and other types of identity "within a few months".[109] As of January 23, 2012 Google+ allows the use of established pseudonyms.[110] In July 2014, Google Plus policy was changed to allow any name to be used.[111]

On November 6, 2013, YouTube began requiring that commenting on its videos be done via a Google+ account. YouTube said that their new commenting system featured improved tools for moderation, and comments would no longer be shown chronologically, but would be featured according to "relevance" and popularity, determined by the commenters' community engagement, reputation, and up-votes for a particular comment.[112] A small portion of channels that used email addresses of older channels without Google account integration, remained without the new comment system, though some older features are now broken.

The decision to require a Google+ account to comment on YouTube videos led hundreds of thousands of users[113] to criticize the change. Some YouTube commenters and content creators complained that the Google+ requirement that users use their real name created online privacy and security concerns.[114] Others said the change made the comment system overly complex, and required users to set up an account on a social media platform for which they had no other use. An online petition to revert the change garnered over 100,000 signatures in less than a week and another 100,000 a week later.[115] YouTube co-founder Jawed Karim voiced his disapproval of the change in one of few recent comments[116][117] and added "I can't comment here anymore, since I don't want a google+ account." to the description of the first ever video on the site.[118] Commenters on YouTube pasted text art tanks and stick figures called "Bob" to protest the new commenting system and Google+.[119] Supporters of the changes said it was a positive step at cleaning up the "virtual cesspool" of homophobic, racist, sexist and offensive comments found on YouTube.[120] However, this actually increased the spam, and in fixing the issue, Google took the opportunity to strike back against those posting "Bob" ASCII art in protest at the company's actions.[121]

On July 27, 2015, it was announced that the integration with Google+ would be discontinued and YouTube would revert to its previous state, requiring only a Google Account to use all the features, such as uploading videos and posting comments. YouTube expects these changes to be rolled out over the course of several months, with the comments feature already having an update: comments now only appear on YouTube and are no longer shared to the social network platform. The ability for content creators to unlink their channel from Google+ has not yet been provided and YouTube urges its users not to delete their page, as it will remove their channel entirely.[40][122]